Double helix sash balance



March 4, 1958 F. J. DECKER ET AL DOUBLE HELIX SASH BALANCE Filed Aug. 9, 1955 U ified} States Pw TO DOUBLE HELIX SASH BALANCE Frederick John Decker, .Pittsford, and Mahlon H. Gregg,

7 Rochester, N. Y., assignors to The Caldwell Manufacturrng C0., a corporation of New York Application August 9, 1955, Serial No. 527,229 a I Claims. cure-197 i This invention relates to window sash balances and of the loaded spring type.

Briefly, the invention comprises a unitary sash balance mechanism having a helical spring mounted on a torque tube which is movable along two spiral rods of different length but havingthe same number of turns.

The lower 15 more particularly to an improved window sash balance fl .C

tube 21 by a screw 24. The flanged portion on tubular".

member 25 is adapted to hold spring 23 in position.

Spring 23 is screwed on to. tubular member 25, and theflanged portion on member 25 prevents the spring from sliding off when spring 23 is subjected to stretching. Spring 23 encircles torque tube 21 and is secured at its upper end to a sleeve member 31 in which torque tube 21 is free to rotate.

remains fixed when tension or compression is applied.

spiral rod is attached to the window sash, so that as the 1 sash is lowered, the spiral rod turns and pulls the torque 1 tube downward, which imparts both tension and torsion to the helical spring. The upper spiral rod stabilizes the torque tube movement and prevents the tube from retracing its original movement, thus holding thesash in the position to which it was moved.

' An object of this invention is to provide a new and improved spring loaded window sash balance which facilitates the raising and lowering of window sashes.

Another object of this invention is to provide a new and improved window sash balance in which the different length and pitch of two spiral rods is utilized to properly load a spring with both tension and torsional forces and to simply hold or release the loaded spring as desired with a minimum of physical effort.

Still another object of this invention is to provide a window sash balance mechanism which is evenly balanced to prevent deleterious friction between the loaded spring and other parts of the mechanism.

A still further object of this invention is to provide a new and improved window sash balance mechanism which is simple and rugged in construction, yet eflicient in operation.

These and other advantages of the invention will be more clearly understood from the following description taken in connection with the accompanying drawings, and its scope will be apparent from the appended claims.

In the drawings:

Figure 1 shows a front view partly in section of th new and improved sash balance mechanism secured to a window frame and sash: and

Figure 2 shows a cross-sectional view of the window sash balance mechanism per se.

The window sash balance embodied in this invention is shown in detail in the cross-sectional view shown in Figure 1. The upper portion of the sash balance 10 is provided with a mounting means 27 which is adapted to be mounted on a window frame by a screw 13. A spiral rod has a flanged end portion 26 fixedly mounted to mounting means 27 which prohibits spiral rod 15 from turning. A torque tube 21 is provided with an ear-shaped end portion 28, which forms an inclined plane surface for contact with the inclined plane surface of the spiral rod, so that torque tube 21 rides on rod 15 as the torque tube 21 is rotated. Ear-shaped end portion 28 of torque tube 21 also prevents the torque tube 21 from contacting any portion of the rod except at the inclined surface at the end thereof which reduces undesired friction. A second spiral rod 16 is positioned in the lower portion of torque tube .21. Spiral rod 16 is adapted to be secured A cover tube 20 encloses the whole assembly and is at-.. tached thereto by an indent made to sleeve member 31v and cover tube 20.

At the upper portion of assembly 10 is a spring 29 'having a collar. Spring'29 bears on an annular projection of sleeve member 31 to which spring 23 is attached. Thus, the initial tension setting on spring 23 can be con-.

trolled by adjusting the tension on small spring 29.

It should be noted that the lower spiral rod 16 is twice the length of the upper sniral rod 15. However, the number of turns in each spiral rod is equal, making a.

steeper pitch in the upper rod.

Inoperation, as rod 16 is moved downward, i. e., by: closing a window sash, nut 30 turns about rod 16.. Rod 16 cannot rotate because it is fixedly mounted by bracket.

14 to a window sash. Since nut 30 is fixed to torque tube 21, the torque tube rotates about rod 16. The torque tube also moves down on spiral rod 15. Thus, spring 23, which is attached to the torque tube, is extended and tensioned with a force equal to the distance travelled on the downward movement of the torque tube on spiral rod 15. At the same time, a torsional force is applied to the spring 23 by the winding action transmitted to the spring by rotation of torque tube 21. Consequently, spiral rods 15 and 16 cooperate to apply both tension and torsion to load spring 23. With the spring 23 loaded in the described manner, there would be a tending for the torque tube 21 to move back up on spiral rods 15 and 16. Spiral rod 16 would offer little resistance to this tendency due to its fast pitch. However, rod 15 has a very slow pitch, the friction of which holds the torque tube in position until a small force is applied; i. e., raising the sash, to overcome this frictional force. Therefore, spiral rod 15 guides, stabilizes, and holds the torque tube 21 in position. It should be noted that torque tube 21 only bears upon spiral rod 15 at its upper extremity, thus eliminating undesired friction between the spring 23, torque tube 21 and the spiral rods 15 and 16. This allows free movement of the elements to facilitate good operation of the sash balance 10.

The carry capacity of spring 23 may be increased by lengthening the upper rod 15 and shortening the lower rod 16, while maintaining the same number of turns in each rod.

Figure 2 shows the sash balance mechanism 10 mounted in a window frame 12 by screw 13. Spiral rod 16 is secured to window sash 11 by a bracket 14. Spring 23 is stretched and wound up as the window sash is lowered. Conversely, spring 23 is compressed and unwound when the sash is raised. The manner in which this is accomplished, which has been set forth herein, offers ease and facility heretofore unobtainable with known sash balances.

Since other modifications and changes varied to fit particular operating requirements and environments will Patented Mar. 4, 1958 Sleeve member 31 has an annular flange 32 on which "spring 23 is wound, so that the spring appeal: obvious to those is not considered limited to the examples chosen for purpose of illustration, and covers all, modification and changes do not depart scope of this invention;

We claim:

1; In a sashibalancehaving a mounting: to be'sccured to a window-frame, a first: spiralrod, fixedly secured: tosaid mounting means, a torque" tube bearing on said first spiral rodfor" rotational movement thereon, asccond spiralti'od; a nut, threaded to receive said second spiral rod, being secured to said torque tube, ai first en teadable' spring: fixedlymounted at its lower extremity tosaid torque. tube, a sleeve member associated with the upper portion of said torque tube, said first spring being fixedly secured ,therctopa seconds spring bearing on an annular projection of said. sleeve member, saidv second spring means for setting the tension at said first spring, and a cover tubesecured to said sleevcmemberr 2. The sashbalance defined in claim 1, wherein: saidsecond spiral rod is greater in length than said first spiral rod, and the number ofturns inlsaid first and second spiral rods are the same.

3. In a window sashbalance adapted to be secured to a window frame and sash, first and second spiral-rods having an equal number Tot turns, means for fixedly securing: the upper endof said first spiral rod, means for fixedly thelowerend of said second spiral rod: to the window sash, a tosque tube riding at its upper end on saidfirst spiral rod for rotational movement thereon, a: nut secured to the'lower end: of said torque tube being rotatably associated with said second spiral rod, a sleeve member associated with the upper endof said torqueitube in which said torque tubelis free to rotare, afirst helical spring, means for securing one end skilled in. the art, the invention from the: trueand oi said first springto the lower end ofi said torque tube and the other end to said sleeve member, a second spring bearing on an annular projection of said sleeve member, said second spring means for setting the tension of said first spring, and a cover tube secured to said sleeve memher.

4. The window sash balance defined in claim 3, wherein said second spiralrod is longer than said first spiral rod.

5. In a sash balance havin'g'a mounting'means adapted to be secured to a window frame, a first spiral rod fixedly secured to said mounting means, a torque tube bearing j on said first spiral rod for rotational movement thereon,

torqueztube', said'first spiral rdd having the same numbe: of: turns as-saidsecond: spiral rod, said second spiral rod being longer than said first spiral rod, a helical spring secured at the' lower extremity of said torque tube and fixedly mounted at its other extremity in the vicinity of saidqfirst' spiral rod to a sleeve member, said sleeve memher having secured to" an annular projection thereof a second spring for adjusting the' tension of said helical spring-a cover tube attached to said sleeve member.

References Cited in'the file of this patent UNITED STATES PATENTS 2,577,953 De Vries et a1 -2..- Dec. 11,1951 2,622,267 Peremi Dec. 23, 1952 2,637,875 Hess May 12, ,1953 2,702,920 De Vries'et al Mar. 1, 1955 

